"Donut Wrold" - aka "Galileo was WRONG; Homer Simpson was RIGHT!"
This is just a totally bizzare yet fascinating concept render of an alternate Earth design. Circa 2005.

Video:
http://www.youtube.com/watch?v=Q1cJW4n6F64
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Okay, let me try to explain the logic behind this:

With the overpopulation growing to epidemic proportions several alternate designs have henceforth been conceived and scrapped. Humankind cannot just simply build a larger planet, because as the surface area squares, the mass cubes, and excessive gravitational pull becomes a serious mobility problem. However, Homer Simpson suggested using the "Donut." As absurd as this may seem, the dynamics actually proved successful. There are two centers of mass on the Torus: One at the center of the minor circumference, and one at the center of the major circumference. In order for this to work for a livable planet, it must rotate at precisely the right speed so that centrifugal force perfectly balances the gravitational pull of the major center of mass. Thus, civilization will be content to live upon the even (or odd, whatever) surface of the Earth. This allows for a huge increase in surface area while still maintaining a stable gravitational force evenly all around the surface. Obviously, the moon cannot orbit around the minor circumference without wreaking havoc on the Earth, so it now resides in a pendulum orbit, passing through the major center of mass (the "hole"), and then losing momentum, until it reverses, and begins to free-fall back towards the "hole" to the other side, repeating the process. An interesting side-effect of this "pendulum" orbit, however, is that the tides now run North and South instead of East and West.

Question is, would such a system actually work???

Except for the moon I think it would be a stable system.

The earth is basically a fluid. What would keep it in the rigid donut shape? Are we talking about a perfect uniform torus rather than a donut planet? Even then I'm not sure the shape would be stable (if it were a fluid).